Apparatus for applying a protective refractory coating to the refractory linings of basic oxygen furnaces



R. J. DEMAISON 3,351,289 APPARATUS FOR APPLYING A PROTECTIVE REFRACTORYNov. 7, 1967 COATING TO THE REFRACTORY LININGS OF BASIC OXYGEN FURNACES3 Sheets-Sheet l Filed May` 6, 1965 N0v 7, 1967 R. .1. DEMAISON .3APPARATUS FOR APPLYING A PROTECTIVE REFRACTORY COATING TO THE REFRACTORYLININGS OF BASIC OXYGEN FURNACES 5 Sheets-Sheet `2 Filed May 6, 1965 INVE NTOR fe 7- EMA/so/v TTOREEYS/ wmv F m um w m. @W ww www mw wm w@ uwmm NOV. 7, 1967 R. J. DEMAISON APPARATUS FOR APP LYING A PROTECTIVEREF'RACTOR COATING TO THE REFRACTORY LININGS OF BASIC OXYGEN FURNACES 3Sheets-Sheet 3 Filed May 6, 1965 @NWN N mmv INVENTOR.`

United States Patent O APPARATUS FOR APPLYING A PROTECTIVE RE- FRACTRYCOATING T THE REFRACTURY LININGS OF BASIC OXYGEN FURNACES Raymond J.Demaison, Bronx, N.Y., assignor to Quigley Company, Inc., a corporationof New York Filed May 6, 1965, Ser. No. 453,688 19 Claims. (Cl.Z39-132.3)

This invention is directed to a method for prolonging the life of thebasic refractory linings of all types of basic oxygen furnaces byspraying a suitable refractory slurry to form protective coatingsthereon.

The words basic oxygen furnaces are used to cover all of the concentrictypes of vessels, from the electric to the Kaldos Linz-Donowitz, DeMays,Grefs rotor, to the basic and acid converters, etc., and will beappreviated as BOF throughout the following description for the sake ofbrevity.

The major problem that has been encountered in the industry to date hasbeen due to the rapid failure of the linings of the BOFs, giving rise toexcessive lining costs per ton of steel produced.

The great rise in the last couple of years of the use of the BOFs in theUnited States has completely changed the normal thinking and methods ofmaking steel. In addition the development of the vacuum process fordegassing steels in the molten state as well as the continuous castingprocess for producing continuous billets have also resulted in majorchanges in the production of end products. It was therefore a normalevolution in the industry to try and produce steels at greater rateswith shorter heat times and the BOFs were the answer. In the normaloperation of the BOFs, the lingings are subjected to extreme conditionsarising from the addition of scrap metal and hot metal as well as theblowing with oxygen to subject the linings to a rapid abrasion, erosionand spalling and result in a repeatable wear pattern in any one furnacewhen operated under the same conditions. In Some instances, specialbrick are used on the side of the vessel to prevent abrasion of thelining on the adddition of scrap metal while in other instances speciallinings are installed in various zones or sectors of the vessel toassist in overcoming said wear patterns. In some instances, thesespecial additions tend to slow down the wear pattern in the particularareas but under no circumstances are they able to keep the Wear patterndown completely, only slow it up. In some extreme wear cases, six inchesof additional refractory material is applied over the face of the entirenew lining subjected to a definite wear pattern to protect it until ithas been thoroughly burned in and set but here again when this is Wornoff the lining receives the normal attack and the wear pattern takesover. The normal wear pattern on the lining runs as high as one-quarterof an inch for every 3 or 4 heats depending on the conditions existingin the furnace during normal operations. The life ot' a normal liningruns from anywhere from 175 to 300 heats and with extreme care beingexercised in the operation of the furnace may run to 35() heats.

The types of linings that are being used are tar-bonded shapes,tar-bonded and tempered shapes or red shapes impregnated with tarorpitch to seal the pores thereof to prevent the moisture from beingabsorbed therein. In some instances, electrically fused cast shapes areused and make it even more ditlicult to repair the linings, as the castshapes are very dense and hard and thus present a surface upon which itis hard to make the refractory materials in slurry form adhere theretofor patching and building up the eroded, abraded and spalled areas asWell as the even overall protective coatings.

The invention was therefore predicated on this background of problemsencountered in the normal operations ICC of the BOFs and the necessityof increasing the life of the linings in order to bring down therefractory cost per ton of steel produced.

It is an object of this invention to provide apparatus for applying aprotective refractory coating to the refractory lining of a basic oxygenfurnace in order to prolong the life of said lining. A shooting pipe forthe refractory coating material equipped with a suitable dischargenozzle is mounted on a long rigid support capable of withstanding thefurnace heat and is arranged for slidable and rotatable movementthereon. The support is mounted on a mobile frat-me which is movableytowards and away from the furnace to effect endwise movement of saidsuport into and out of the furnace. The mobile frame is equipped with ashield for protecting the operator from the furnace heat in theoperation of the apparatus and said shield contains a supporting rollupon which the shooting pipe support rests and fulcrums for movementthereon to allow for endwise movement of the support into and out of thefurnace and in addition allow for both vertical and horizontal rockingmovements which in cooperation with the movement of the shooting pipeassures the possibility of moving and locating the discharge nozzle inany selected position inside the furnace to spray any and all areasdeemed necessary to prolong the life of said lining.

It is also an object of this invention to enable the operator tocompletely control the discharge nozzle in both the horizontal andvertical directions to enable him to first repair the abraded, erodedand spalled areas of the lining by the application of a suitable numberof protective coatings, one over another, to bring the lining thicknessin these areas up to the lining thickness of the surrounding areas andthen apply over the whole lining area a suitable number of protectivecoatings, one 4over another, to further cover and protect the wearpattern areas and in addition protect the rest of the lining as well.The prime idea is to keep the lining at a sufficient thickness bybuilding up the wear pattern areas and the overall lining area toprevent failure of said lining before a desired number of heats has beenobtained thereon. -It is entirely conceivable that, if the lining issutiiciently protected at the beginning of a campaign, the lining lifemay be extended to well over 800 heats. In the eld, by the use of theinstant invention it has already been possible to obtain over 700 heatsby simply maintaining the lining thickness at such a value as to preventthe failure thereof until a desired number of heats is obtained and thusmore than double the normal life expectancy of the lining and reduce therefractory cost per ton of steel produced.

Another object of this invention is to provide a cornpletely retractableshooting pipe arrangement which can be completely removed from saidfurnace for storage, cleaning or movement to the next furnace for usetherein. The shooting pipe may be water cooled if desired to allow thecontinuous spraying of the protective refractory coating material ontothe furnace lining without necessitating the withdrawal of the unitforcooling. In addition, where larger furnaces are to be sprayed overlonger periods of time, the long rigid support may also be water cooled.

A further object of the invention is to provide a protective means forthe operator or operators in the form of a shield equipped with asuitable heat resisting and insulating lining and having a suitableplurality of inspection openings containing safety screens therein forobserving and controlling the movement of the long rigid support for theshooting pipe. In this manner it is possible to protect the operatorfrom the high temperatures prevailing in the furnace and allow him toobserve and control the spraying operation without too much discomfort.In addition, the shield is equipped with suitable means in the form ofrollers contained in the opening in the shield to allow the shootingpipe support to be slid 3 into and out of the furnace as well as toallow for vertical and horizontal rocking movements of said support topermit the discharge nozzle to be located in different selected verticaland horizontal positions within the furnace.

The instant invention is directed to an apparatus for applying aprotective refractory coating to the refractory lining of a basic oxygenfurnace while it is at or near operating temperature in order to prolongthe life of said lining. The apparatus disclosed herein is complete inits ability to allow the application of suitable protective refractorycoatings to rst build up the eroded, abraded and spalled areas then toreplace the refractory material which has been removed by the normalfurnace operation. The net result is easily and quickly explained in theability of the refractory coating materials used to form the refractorycoatings to be retained on the face of the lining and not reacttherewith in a deleterious manner but rather to react therewith to formcompounds of higher refractoriness and in addition have the ability toreact with the iron oxide in the slag and thus prevent it from reactingwith the lining to produce compounds of lower refractoriness. Thesubsequent layers of the protective refractory coatings with the slagdeposited in between said layers react to form a monolithic facing overthe lining which protects said lining; and, if said coatings were beingcontinually replaced as is envisaged in the present invention, they willresult in a continuous lining thickness and cause the lining life to beextended still further. If a suitable plurality of the protectiverefractory coatings were continuously maintained at a more or lessconstant rate without interfering too much with production, it would bepossible to have the bricks forming the lining stand up for much longerperiods of time without deteriorating internally.

Other objects and advantages of the invention will readily becomeapparent by a thorough consideration of a preferred embodiment thereof:

FIG. 1 is a side view of the long rigid support for the shooting pipecapable of withstanding the furnace heat and clearly shows the shootingpipe for the refractory coating material equipped with -a suitabledischarge nozzle;

FIG. 2 is an enlarged cross-sectional view of the long rigid support forthe shooting pipe shown in FIG. l taken along the line 2-2 in thedirection of the arrows and clearly depicts the means for rotatably andslidably mounting the shooting pipe;

FIG. 3 is a side view of the long rigid support for the shooting pipeshown in FIG. l in place in a BOF and clearly shows the mobile frame inwhich it is mounted and by which it may be moved endwise into and out ofthe furnace when said furnace occupies a substantially horizontalposition;

FIG. 4 is a side view of a liquid cooled long rigid support for theshooting pipe;

FIG. 5 is an enlarged side view of the liquid cooled long rigid supportshown in FIG. 4 to more clearly show the water inlet and outlet pipesand the flow pattern created within the support to assure even coolingof the unit;

FIG. 6 is a cross-sectional view of the liquid cooled long rigid supportof FIG. 5 taken along the lines 6--6 in the direction of the arrows;

FIG. 7 is a 4cross-sectional view of the liquid cooled long rigidsupport of FIG. 5 taken along the lines 7-7 in the direction of thearrows;

FIG. 8 is a cross-sectional view of the liquid cooled long rigid supportof FIG. 5 taken along the lines 8 8 in the direction of the arrows; and

FIG. 9 is 'a side view of the liquid cooled long rigid support shown inFIG. 4 in place in a BOF and clearly shows the manner in which theshooting pipe is mounted in the mobile frame.

In FIG. 1, there is shown hte long rigid support 10 for the shootingpipe 24, which support is capable of withstanding the furnace heat. Theshooting pipe is equipped with a suitable discharge nozzle 31 for therefractory coating material and is rotatably and slidably mounted on thesupport. The support 10 has a counterweight 11 at its outboard end tobalance the support on the rollers 12 (seeFIG. 3). The counterweight 11is made up of small weights and may be varied in value by the removal oraddition of the weights so as to keep the support in balance formaneuverability at all times. The support 10 is fabricated of fourlongitudinally arranged angles 13, 14, 15 and 16, as shown in this View.The vertical bracing consists of bars 17, 18,/

19 and 20 which are welded in place as shown, and the number andplacement of these bars will depend upon the length of the support andthe size and weight of the shooting pipe 24 to thus form a long rigidbalanced shooting pipe support which has its center of balance at thepoint 21 where the vertical braces are placed to distribute the loadingto the top member 14V and also provide a point for disassembly. Thebottom of the support is dat and it is therefore possible to slide thesupport upon the rollers 12 into or out of the furnace the necessarydistance to allow spraying in various selected positions and in additionallow for horizontal and vertical rocking movements of the support uponthe rollers. The shooting pipe 24 is placed longitudinally along the topof the support 10 in the brackets 25, 26, 27, 28 and 29' which arearranged to freely allow the insertion and turning of the shooting pipe24` `in the holes 30 as well as to allow it to be moved back and forthin an endwise direction. The shooting pipe support 10 is divided into aplurality of sections and the sections bolted together, as shown in FIG.l, but the brackets 25, 26, 27, 28 and 29 for the shooting pipe willremain the same and will be lined up to accept the pipe therein. In mostall instances, it will be preferable to sectionalize the support 10 atthe point 21 to allow the counterweighted rear section thereof to behandled separately as a small section. It may also be desirable to makethe main portion of the support in two sections, one of which may bearranged to hinge upwardly, as shown at 22, and fold over the other halfto avoid problems in storage. In order to do this the shooting pipewould be withdrawn.

The far side of the shooting pipe support, looking at FIG. 2, will besimilarly constructed and the complete unit will therefore form a longstiftc beam. Likewise the top and bottom of the support will besimilarly formed with suitable stiifeners along its length. It will benoted that the counterweighted end of the support beyond the roller 12is sloped gradually downwardly to provide space above it to manipulatethe shooting pipe 24. T he same is true of the long section of thesupport which is inserted into the furnace, but here the top is keptstraight and the bottom slopes upwardly toward the end of the' supportwhile the two vertical sides remain parallel. This is also done for afurther reason, namely, to keep down the weight and give a straight datsurface upon which the support may be rolled into and out of the furnacebut in no case does the shape affect the supports rigidity. The supportmay also be made of other shapes, such as triangular, hexagonal, etc.,depending upon the circumstance and equipment available to handle it.The support may be fabricated of ordinary steels where short sprayperiods will be used, but where longer spray periods are encountered itis desirable to use stainless steels entirely.

The shooting pipe 24 is inserted into the support 10 from thecounterweighted end and once inserted the spray nozzle 31 may be screwedin place and thus be ready for spraying. The spray nozzle 31 is arrangedwith an angularly disposed discharge portion 32 and its outboard end isclosed by means of a cap 33, while the body of the nozzle is fastened tothe shooting pipe 24 `by means of coupling 34 to make it possible, whendesired, to reverse the nozzle on the end of the shooting pipe when itis necessary to spray the neck portion of the furnace. The spray nozzle31 may be made with the discharge portion 32 at various angles from 30to 90 to thus cover the entire periphery of the furnace from top t0bottom. If the shooting pipe support is Very long and greater rigidityis desired, it is possible to use angle for the vertical and horizontalcross braces. The smaller.'

or nozzle end of the support is formed by a square of angles with crossbracing therein welded together with the longitudinal angles weldedthereto to form a rigid end (see FIG. 2). The support 10 may be designedfor liquid cooling by substituting tubing or pipe for the angles andinserting a pressure tank at the small end which is inserted into thefurnace and by using two of the longitudinal pipes to supply cool liquidto the tank and two pipes to return the warm liquid for discharge orrecooling, as desired. As a precautionary measure, the warm liquid pipesshould be fitted with safety valves in case vapor is generated in thepipes due to cooling liquid flow failure.

The discharge nozzle 31 may also be used to measure the thickness of thelining in the furnace. A series of offsets from the centerline of thefurnace may be worked out to determine from these offsets, using thelength of the boom and the subtended angle of the boom from thecenterline of the furnace, a particular offset which will, when usingthe inside face of the shell of the furnace as the reference point, givethe remaining thickness of the lining. The shooting pipe 24 may also bescribed or punchmarked to indicate the length protruding beyond thesupport 10 to form a control means for locating the spray nozzlelongitudinally in the furnace when particular areas are to be sprayed.In addition the location of the discharge portion 32 can also be markedso that the operator can more closely control the spray pattern. It iseven possible to clamp a split gear over the shooting pipe 24 and make aturning device for continuously rotating it or for turning it throughdefinite angles and thus spray selected areas to still further simplifythe control of the spray pattern. Where it is desired to rotate theshooting pipe completely around or in wide areas, the pipe will befitted with a ball joint 52 at its outboard end which will allowcomplete freedom of movement without having to ltwist or turn theflexible conduit 53 supplying the slurry to the shooting pipe. It canthus be seen that the support 10 for the shooting pipe 24, with thereversible spray nozzle 31 mounted thereon, is of extreme importancebecause, without it, it would be diicult or impossible to spray therefractory material onto the lining, since the spray pipe alone gets hotand bends and would deect from the reaction force of the issuing sprayand make it extremely hard to cover definite areas of the furnacelining.

FIGS. l and 2 disclose the long rigid support in its simplest form; moreexotic forms will later be disclosed for use in larger furnaces, wherelonger supports are necessary and Where longer spraying periods arenecessary.

In designing the shooting pipe support 1i), the size of the furnace isof necessity the prime factor which will control its length, as it mustbe possible to reach the entire area of the furnace lining. Afterdetermining the length of the support, it will then be necessary todetermine the shooting pipe size and its weight when filled withsprayable slurry as Well as the time necessary to build up the liningand subject the support to the heat of the furnace during that period.We Will then have all the controlling factors for the design of thelightest unit possible and one with the greatest rigidity and mobilityand with the necessary heat resistance, If very long shooting periodsare to be used, as in the larger furnaces (250 tons to 350 tons),recourse Will have to be made again to liquid cooling which will againadd weight to the support and necessitate further design to take care ofthe added weight and the possibility of vapor generation in the coolingsystem. As a note of caution, when liquid cooling is used, completetesting of the unit under extreme pressures and temperatures arenecessary to insure tightness and rigidity because, if during use in thefurnace a liquid leak develops, the possibility is that the lining Willbe badly spalled.

FIG. 3 discloses, in connection with the furnace 38 which occupies asubstantially horizontal position, the mobile frame 35 in which the longrigid support 10 is mounted. This frame 35 is capable of movement on theoor 37 towards and from the furnace 38 to thus control the endwisemovement of the long rigid support 10 in and out of the furnace 38. Themobile frame 35 is equipped with the chain hoist 36 which is connectedto the support 10 at its counterweight end 11 and is movable with thesupport during such movements.

The mobile frame 35 consists of an inverted U-shaped frame arrangementhaving an overhead I beam 41 supported on two inverted U-shaped supports42 and 43 equipped with wheels 44 and 45 to allow the whole frame to bemoved about on the oor 37. The supports 42 and 43 are diagonally bracedto the I beam 41 by means of angular braces 46 and 47 to stiffen thewhole assembly and make it extremely rigid. The carriage 48 is arrangedto mn on the bottom ange of the I beam 41 having the two sets of wheels49 and 50 (one side only shown, duplicate set on other side of beam toride on flange of beam) upon which it will be moved to thus maneuver thesupport 10 within furnace 38. The carriage 48 is arranged to support thechain hoist 36 to assist in effecting the maneuvering of the support 10in the furnace and, as stated above, the chain hoist is secured to thecounterweighted end 11 of the support 10 through an extension 10a viachain 51, whereby the support 10 can be vertically or horizontallyrocked on the rollers 12 as well as slid into or out of the furnace onthe I beam 41 and the rollers 12. The support 42 is used to carry theshield 39 containing the opening 40 through which the long rigid support10 may be moved back and forth on rollers 12 or swung sideways in thefurnace. The shield 39 is fastened to the support 42 by eans of brackets55 and 56 and is completely fabricated of steel plate and angles and islined with insulating refractory material to protect the operator fromthe furnace heat. Where extremely long periods of shooting are used, theshield 39 may be fitted with suitable additional windows containingtinted shatter and heat proof glass or steel screening for operatorprotection and comfort. The lower end of the shield is equipped withadditional wheels 44a where very heavy long rigid supports 10 are usedin order to insure that the back wheels 45 will stay on the floor 37without adding weights to the support member 43.

The shooting pipe 24 is arranged at its outboard end with a suitablerotary joint 52 interposed between said pipe and conduit 53 to allow theshooting pipe to be rotated and moved back and forth on the support. Theconduit 53 is connected to a suitable mixer arranged to supplyrefractory material thereto in proper form for spraying. The shootingpipe 24 may also be arranged at the outboard end to mix the refractorymaterial in said shooting pipe by adding a mixing chamber for thematerial and water and to form the sprayable slurry therein.

The extension 10b is controlled and contained by a circular ring ofsuitable diameter to allow the support 10 to be maneuvered in thefurnace to spray the lining in a circular pattern and thereby furnish anadditional means to control the spray pattern within the furnace. Thecircular ring 100 is suspended from the beam 41 by means of the clamp101 and the depending support 102 to thereby form a rigid guide meansfor controlling the spray pattern within the furnace 38.

FIG. 4 is a side view of a liquid cooled long rigid support 55 in theform of a tubular liquid cooled version with the shooting pipe 24mounted internally therein for complete rotation as well as for lateralmovement, whereby it is possible to spray complete sections of thefurnace lining as Well as to allow abraded, eroded and spalled Iareas tobe built up with extreme accuracy and control.

The support 55 is completely fabricated from tubing and annular rings ofsuitable sizes and poses no problem in assembling. The center tube 56 istted with four annular rings 57, 58, 59 and 60 welded in place on thecenter tube 56 as shown; annular ring 57 has no openings therein and isarranged to receive the tube 61 on its outside circumference to form theend closure for the tubular liquid coolant passage; annular ring 58 isalso welded in place on the center tube 56 and outer tube 61 as shown toform the liquid coolant reservoir at the inboard end of the supportwherein the flow of liquid coolant is reversed; and ring 58 is formedwith a suitable plurality of holes arranged to receive the ends of thetubes used to supply the liquid coolant to the unit and in addition hasholes for the coolant to flow therethrough and return through the outertube. The annular ring 59 is formed with the same plurality of holes asthe ring 58 and is welded on its inside face to the tube 56 and on itsouter face to the tube 61, and the liquid coolant supply tubes arewelded into the holes contained in the rings 58 and 59 to thus form themeans for supplying the inboard end reservoir with the liquid coolant.The annular ring 60, with the liquid coolant inlet 62 on its outsideface, is then welded in place on and in the tubes 56 and 61 to form theliquid coolant entrance reservoir and supply the liquid coolant to thetubes, carrying it to the inboard reversing flow reservoir containedbetween the annular rings 57 and 58. The use of the tubes here is moreor less of a necessity, as the liquid coolant in the whole length of thetubes contained between tubes 56 and 61 must be cooled, and the liquidcoolant entering the passages in the tubes is at the lowest temperatureand will therefore continuously cool the liquid coolant beyond thenormal ow pattern. The return fiow tube 63 is then installed, using thetwo annular rings 64 and 65 and welding the whole assembly into place toform the return liquid coolant passage with the pipe 66 contained on theoutside face of the ring 65, carrying all the hot liquid coolant out forcooling and returning into inlet pipe 62. It will be noted that the tube61 is formed with a suitable number of radial holes in its peripherybeyond the annular ring 64 to allow the coolant to ow outwardly into thepassage between the two tubes 61 and 63 and thus allow the hot liquidcoolant to be ejected outwardly into the rearwardly directed passage fordischarge therefrom. The design of the long rigid support 55 is such asto insure maximum coolness of the inboard end and also to allow the unitto be balanced on its outboard extending portion to facilitate itsmaneuvering in the furnace. In designing the support, cognizance willhave to be taken of the weight of the coolant contained therein in orderto get proper balancing; and, in view of the extended periods ofspraying used with this type of support, the use of stainless steels arenecessary in the fabrication and welding of the unit. This is alsoparticularly desirable if water is used as a coolant, as the stainlesssteels will obviate the formation of rust and scale and eliminatepossible clogging of the tubes or passages.

In reference to FIG. 6, the annular ring 58 is welded in place betweenthe two tubular members 56 and 61 concentrically mounted and arranged toaccept the four tubes 70, 71, 72 and 73 mounted and welded thereto tocarry the liquid coolant therein to the inboard reversing reservoir. Theannular ring 58 is also formed with four additional holes having thesame cross-sectional area as that of the liquid supply tubes and equallyspaced between the tube inlets to allow the liquid coolant to flowtherethrough and keep a constantly replaced reservoir of the liquidcoolant in the inboard reservoir, which is subjected to the greatestheat, and circulate back through the support cooling it enroute stillfurther and nally allow it to ilow outwardly through the radiallydrilled holes in tube 61 into the space between the concentric tubes 61and 63 and then empty out in pipe 66. It will be seen that the design ofthe support is such as to preclude the formation of hot spots and hightemperature differentials of said liquid coolants flowing therein,thereby insuring even temperature gradients to be set up over the entirelength of said support to insure continued even cooling with nofailures.

FIG. 7 is a cross-sectional view of the liquid cooled long rigid support55 taken along the lines 7 7 of FIG, 5, and shows the radial holes inthe tube 6]. so placed as to allow the liquid coolant flowing back fromthe inboard reversing reservoir to be discharged radially into the spacebetween the two tubes 61 and 63 and then discharged into water outlet66. The complete theory of the operation of the coolant system is toallow the cold water to enter the tubes and be conveyed to the inboardreversing reservoir but in so doing the water is warmed rst by the watersituated beyond the radial holes or beyond the normal flow pattern (tohelp keep this cool), then is further warmed by the return flow of hotwater returning from the reversing reservoir and then to be dischargedinto the reversing reservoir for further warming and ow outwardly to theoutlet pipe. In this manner, the water is warmed up in steps and notejected as cold water into the reversing reservoir.

Referring to FIG. 8, the annular ring 59 is welded in place between thetwo tubular members 56 and 61 concentrically mounted and arranged toaccept the four tubes 70, 71, 72 and 73 mounted and welded thereto tocarry the liquid coolant therein to the inboard reversing reservoircontained between the annular rings 57 and 58 and in addition to coolthe liquid coolant contained in the reservoir beyond the holes in thetube 61. The arrangement shown discloses the dual role of the tubes 70,71, 72

and 73 in the carrying of the liquid coolant therethrough, and it can bereadily seen that this arrangement insures that there will be no hotspots or areas with extreme ternperature differentials developed in theliquid coolant system which could cause serious trouble. The liquidcool-` ant outlet pipe 66 should be fitted with a pressure relief valveset to relieve the pressure in the system at from 50# to 75# above thepressure used in the liquid coolant system. This precaution is desirablebecause it is conceivable that something could happen to the liquidcoolant supply system and with the high temperatures developed andexisting in the furnace, it would not be long before the liquid coolantwould be vaporizing and creating high pressures therein which couldcause failures in the support if not promptly relieved.

In the water cooled version of the long rigid support 55, the supportand control means 75 used to control the movement of the support 55consists again of a mobile frame in the shape of an inverted U-framearrangement having an overhead I beam 76 supported on two invertedU-shaped supports 77 and 78 equipped with wheels 79 and 80 to allow thewhole frame to be moved about on the oor 37. The supports 77 and 78 arediagonally braced to the top of the I beam by means of braces 81 and 82,and it will be noted that the I beam 76 is suspended under the U-shapedsupports 77 and 78 and that the braces 81 and 82 also go to the top ofthe I beam to thus leave the bottom flange clear for the entire lengthbetween supports. This combination of the supports and the diagonalbracing stiffens the whole assembly and makes it extremely rigid whilestill allowing the carriage 83 on the bottom ange of the beam to bemoved from one end of the beam to the other without any diiculty. The Ibeam 76 is arranged to accept the carriage 83 having two sets of wheels84 and 85 (one side only shown, duplicate set on other side to ride onflange of beam) upon which it will be moved to thus maneuver the support55 within the furnace 38. The carriage 83 is arranged to support thechain hoist 86, which is secured to the support 55. The support 55 isarranged with a circular ring 87 and the lifting chain of the chainhoist 86 is placed in the deep groove of the ring 87 to form the liftingmeans. In addition, the circular ring S7 is made in halves which aresecured together by means of bolts and wing nut to render said ringreadily movable along the length of the outboard section of the support55. It will be noted that the extreme outboard end of the support 55 isequipped with a counterweight 88 secured by means of a chain 89 in thering 90, which latter is also a split ring and may be moved. It isevident therefore that the two means'of controlling the maneuverabilityof the support 55 are the chain hoist and its positioning thereon andthe counterweight with its positioning and weight control, providing aninfinitely varying control means. The support 55 is equipped with thewater inlet pipe 62 and water outlet pipe 66 to which hoses 91 and 92are connected to allow liquid coolant to be circulated therethrough andkeep said support cool for longer periods of time and therefore allowlonger spray periods to be used than would be possible without cooling.

The liquids used for cooling can be water, Prestone or any other liquidwhich will carry off heat and not cause any contamination problems. If aconstant source of coolant liquid is not available, a cooling tower canbe resorted to or a heat exchanger put in the circuit to cool theliquid.

The shooting pipe 24 contained in the support 55 is supplied withrefractory coating material of suitable viscosity by means of conduit 53with the rotary joint 52 interposed between said pipe and conduit toallow the shooting pipe to be rotated completely or partially as thespray pattern demands.

The outboard end of the shooting pipe may be equipped with suitableindicating means to show the angle of discharge of the nozzle as well asthe positioning in the furnace. The shooting pipe may also be equippedwith suitable apparatus to continually turn it at any given rate desiredin order, when an overall spray coating is desired, to move the shootingpipe longitudinally at a constant rate and accomplish this feat withoutany problem.

A further variation of the instant disclosure is to make two concentrictubes separate and distinct one from the other and allow the innerliquid cooled tube to be moved inside the outer liquid cooled tube forfurther variations in design and construction which will provide greaterlatitude in operation than that already disclosed herein.

The mobile frame 75 of the second embodiment shown in FIG. 9 is alsofitted in this instance with a shield 95 fastened on the support 77 andis formed with the opening 96 through which the support 55 may be movedinto and out of the furnace as well as rocked both vertically andlaterally to locate the discharge nozzle in different selected positionswithin the furnace. The shield 95 is also lined with a suitable lightweight refractory or other heat insulating lining capable ofwithstanding the heat of the furnace to protect the operators and stillallow them to see what they are doing inside the furnace. The mobileframe 75 of FIG. 9 may also be used with the shooting pipe support 10shown in FIGS. l, 2 and 3 where it is desired to facilitate the movementof said support into and out of the furnace. The support 10 will bemounted on a heavy prefabrica-ted yoke equipped with a roller arrangedacross the bottom of the yoke. The yoke is then mounted on a hook of thechain .hoist 86 and said chain hoist will allow the balanced support tobe moved up and down on the carriage 83 and the whole apparatus can bemoved on the beam 76. Such an arrangement allows for complete freedom ofmovement of the support without resorting to rollers on the shield 95,In this manner, the mounting of the support is completely divorced fromthe shield.

It may also be noted that the shield 95 of FIG. 9 and the shield 39 ofFIG. 3 may be made in the form of hinged sections which may be foldedtogether for ease of movement of the mobile frame on the floor.

It is also possible to use the instant designs or their equivalent forsupports and apply them to such equipment as pay loaders, etc. or tocars designed to run on the rails alongside the BOFs. In these instancesthe supports may be designed to telescope, one section within the other,and be mechanically, electrically or hydraulically actuated, and mayeven be water cooled where large furnaces are to be sprayed for longperiods of time. This type of equipment will also allow the shootingpipe to be inserted inside or nested on the outside, depending on thedesign of the support and the actuating means employed. It is alsopossible to use the supports disclosed herein and use either air or oilfor actuating cylinders which will dispense with the chain hoists per sebut will still necessitate means to move the supports into and out ofthe furnace.

The long rigid support, the shooting pipe equipped with a suitabledischarge nozzle, the mobile frame and the equipment for handling thelong rigid support therefore form a combination which allows theapplication of protective refractory coatings to the refractory 1iningof a basic oxygen furnace while it is at or near operating temperature.In addition the same apparatus can be used on occasions to applyprotective refractory coatings before the furnace is put in operation tofurther protect the lining when the furnace is put on the line.

The means for controlling the spray pattern and called herein thedischarge nozzle has been covered by an issued Patent No. 2,997,244while a further version is disclosed in copending application Ser. No.402,203, filed Oct. 7, 1964.

The apparatus of this application is :specifically designed for thepractice of the process disclosed in copending application Ser. No.424,071, led Jan. 7, 1965.

The refractory material used for the repair and coating of the furnacelinings may be of any type so long as it is suitable and effective forthe practice of the invention as herein described. However, reference ismade to the three following patents owned by the assignee of the instantapplication as examples of suitable refractory materials:

No. 2,809,126, dated Oct. 8, 1957, wherein the coating compositionconsists primarily of chrome ore;

No. 3,093,496, dated June 11, 1963, wherein the coating compositionconsists of a mixture of chrome ore and magnesia but wherein the chromeore predominates;

No. 3,093,497, dated June 1l, 1963, wherein the coating compositionconsists of a mixture of chrome ore and magnesia but wherein themagnesia predominates.

Reference is also made to Patent No. 3,093,458, dated I une l1, 1963,also owned by the assignee of the instant application, and whereinrefractory compositions of different refractoriness are employed inbuilding up a multiple layer coating.

Another refractory material which may be used for the repair and coatingof the furnace linings is disclosed in the copending Dreyling et al.application Ser. No. 173,839, filed Feb. 16, 1962, which materialconsists essentially of dead burned or fused magnesite containingcertain binding and barrier materials.

Different types of spraying apparatus may be employed in carrying outthe process and reference is made to the following patents all owned bythe assignee of the instant application:

No. 2,700,535, dated Ian. 25, 1955 No. 3,114,536, dated Dec. 17, 1963Reference is also made to the following copending applications whichalso disclose further types of spraying apparatus that may be used incarrying out the instant process:

Demaison application Ser. No. 319,001, filed Oct. 25,

1963 now Patent No, 3,248,093

Demaison application Ser No. 383,416, filed July 17,

Demaison application Ser. No. 402,203, led Oct. 7,

What is claimed is:

1. An apparatus for applying a protective refractory coating to therefractory lining of a basic oxygen furnace while it is at or nearoperating temperature in order to prolong the life of said lining,comprising in combination, a long rigid shooting pipe for the refractorycoating material equipped with a suitable discharge nozzle, a long rigidsupport for the shooting pipe capable of withstanding the furnace heatand adapted to 4be moved endwise into and out of the furnace when thelatter occupies a substantially horizontal position, the length of saidsupport being substantially equal to the length of the furnace liningand a mobile frame carrying said support and located on a platform inproximity to the furnace, said support extending longitudinally of themobile frame and when located out of the furnace projecting toward thefurnace for a substantial distance from the furnace confronting end ofthe mobile frame, and said mobile frame being freely maneuverable on theplatform to locate the shooting pipe support in position to enter thefurnace at different angles and then movable toward and from the furnacein effecting the movements of the support into and out of the furnace.

2. An apparatus according to claim 1, wherein the support is movabledifferent distances into the furnace by the movement of the mobile framealone to locate the discharge nozzle in different selected endwisepositions therein in applying the protective refractory coating to thefurnace lining.

3. An apparatus according to claim 1, wherein the shooting pipe supportis slidably mounted `on the mobile frame for endwise movement withreference thereto to vary the endwise position of the discharge nozzlewithin the furnace while the mobile frame remains stationary.

4. An apparatus according to claim 1, wherein the shooting pipe supportis mounted on the frame for a vertical rocking movement in its own planeto locate the discharge nozzle in different selected vertical positionswithin the furnace after the support has been moved endwise into thefurnace by the mobile frame.

5. An apparatus according to claim 1, wherein the shooting pipe supportis mounted on the frame for a lateral rocking movement in its own planeto locate the discharge nozzle in different selected lateral positionsWithin the furnace after the support has been moved endwise into thefurnace by the mobile frame.

6. An apparatus according to claim 1, wherein the shooting pipe supportis mounted on the frame for both vertical and lateral rocking movementsin its own plane to locate the discharge nozzle in different selectedvertical and lateral positions within the furnace after the support hasbeen moved endwise into the furnace by the mobile frame.

7. An apparatus for applying a protective refractory coating to therefractory lining of a basic oxygen furnace while it is at or nearoperating temperature in order to prolong the life of said lining,comprising in combination, a shooting pipe for the refractory coatingmaterial equipped with a suitable discharge nozzle, a long rigid supportfor the shooting pipe capable of withstanding the furnace heat, a mobileframe carrying said support and located on a platform in proximity tothe furnace, said frame being movable toward and from the furnace ineffecting an endwise movement of the support with the shooting pipethereon into and out of the furnace when the latter occupies asubstantially horizontal position, and means for mounting the shootingpipe support on the mobile frame for a vertical rocking movement whensaid support is moved endwise into the furnace in order to locate thedischarge nozzle in different vertical positions within the furnace,said mounting means including a supporting roller upon which theshooting pipe support rests and fulcrums.

8. An apparatus for applying a protective refractory coating to therefractory lining of a basic oxygen furnace while it is at or nearoperating temperature in order to prolong the life of said lining,comprising in combination, a shooting pipe for the refractory coatingmaterial equipped with a suitable discharge nozzle, a long rigid supportfor the shooting pipe capable of withstanding the furnace heat, a mobileframe carrying said support and located on a platform in proximity tothe furnace, said frame being movable toward and from the furnace ineffecting an endwise movement of the support with the shooting pipethereon into and out of the furnace when the latter occupies asubstantially horizontal position, and means for mounting the shootingpipe support on the mobile frame for a vertical rocking movement whensaid support is moved endwise into the furnace in order to locate thedischarge nozzle in different vertical positions within the furnace,said shooting pipe support being provided at its end remote from thedischarge nozzle with a weight to locate the balance point of thesupport near said end.

9. An apparatus for applying a protective refractory coating to therefractory lining of a basic oxygen furnace while it is at or nearoperating temperature in order to prolong the life of said lining,comprising in combination, a shooting pipe for the refractory coatingmaterial equipped with a suitable discharge nozzle, a long rigid supportfor the shooting pipe capable of withstanding the furnace heat, a mobileframe carrying said support and located on a platform in proximity tothe furnace, said frame being movable toward and from the furnace ineffecting an endwise movement of the support with the shooting pipethereon into and out of the furnace when the latter occupies asubstantially horizontal position, and means for mounting the shootingpipe support on the mobile frame for a vertical rocking movement whensaid support is moved endwise into the furnace in order to locate thedischarge nozzle in different vertical positions within the furnace,said mounting means including an overhead trolley adapted to run on atrack extending fore-and-aft of the mobile frame.

10. An apparatus according to claim 9, wherein the connection betweenthe shooting pipe support and the overhead trolley includes a chain andpulley arrangement for raising and lowering the support with referenceto the mobile frame.

11. An apparatus according to claim 9, wherein the overhead trolley isconnected to the support at a point about which it rocks.

12. An apparatus according to claim11, wherein the shooting pipe supportis provided at its end remote from the discharge nozzle with a weightwhich balances the support about its rocking point.

13. An apparatus according to claim 11, wherein the connection betweenthe shooting pipe support and the overhead trolley is such as to permitthe support to be rocked laterally as well as vertically at its rockingpoint.

14. An apparatus for applying a protective refractory coating to therefractory lining of a basic oxygen furnace while it is at or nearoperating temperature in order to prolong the life of said lining,comprising in combination, a shooting pipe for the refractory coatingmaterial equipped with a suitable discharge nozzle, a long rigid supportfor the shooting pipe capable of withstanding the furnace heat, andmeans whereby said support with the shooting pipe thereon may be movedendwise into and out of the furnace when the latter occupies asubstantially horizontal position, said shooting pipe support being inthe form of a cylindrical water jacket surrounding the shooting pipe butseparate and distinct therefrom and comprising a series ofconcentrically disposed water circulating pipes extending substantiallythroughout the length of the jacket.

15. An apparatus according to claim 14, wherein certain of saidcirculating pipes are connected to a water inlet andthe remaining pipesto a water outlet.

16. An apparatus according to claim 14, wherein the Water jacket isformed at one end with a water space con nected to a water inlet andcommunicating with certain of the water circulating pipes at one end andwherein said jacket is formed at the opposite end with a similar waterspace connected with a water outlet as well as with the remaining watercirculating pipes at the opposite end.

17. An apparatus for applying a protective refractory coating to therefractory lining of a basic oxygen furnace while it is at or nearoperating temperature in order to prolong the life of said lining,comprising in combination, a shooting pipe for the refractory coatingmaterial equipped with a suitable discharge nozzle, a long rigid supportfor the shooting pipe capable of withstanding the furnace heat, a mobileframe carrying said support and located on a platform in proximity tothe support, said frame being maneuverable on the platform to locate theshooting pipe support in position to enter the furnace, and means formounting the shooting pipe support in the mobile frame for endwisemovement with reference to the frame when so positioned in order to movethe support with the shooting pipe thereon into and out of the furnacewhile the frame remains stationary, said mounting means including anoverhead trolley adapted to run on a track extending fore-and-aft of themobile frame.

18. An apparatus for applying a protective refractory coating to therefractory lining of a basic oxygen furnace while it is at or nearoperating temperature in order to prolong the li-fe of said lining,comprising in combination, a shooting pipe for the refractory coatingmaterial equipped with a suitable discharge nozzle, a long rigid supportfor the shooting pipe capable of withstanding the furnace heat, a mobileframe carrying said support and located on a platform in proximity tothe support, said frame being maneuverable on the platform to locate theshooting pipe support in position to enter the furnace, and means formounting the shooting pipe support in the mobile frame for endwisemovement with reference to the frame when so positioned in order to movethe support with the shooting pipe thereon into and out of the furnaceWhile the frame remains stationary, said mounting means including aroller upon which the shooting pipe support rests and moves and anoverhead trolley adapted to run on a track extending tore-and-aft of themobile frame.

19. An apparatus for applying a protective refractory coating to therefractory lining of a basic oxygen furnace while it is at or nearoperating temperature in order to prolong the life of said lining,comprising in combination, a shooting pipe for the refractory coatingmaterial equipped with a suitable discharge nozzle, a long rigid supportfor the shooting pipe capable of withstanding the furnace heat andadapted to be moved endWise into and out of the furnace when the latteroccupies a substantially horizontal position, and a mobile framecarrying said support and located on a platform in proximity to thefurnace, said support when located out of the furnace projecting towardthe furnace for a substantial distance from the furnace side of themobile frame, and said mobile frame being maneuverable on the platformto locate the shooting pipe support in position to enter the furnace andthen movable toward and from the furnace in effecting the movements ofthe support into and out of the furnace, characterized in that theshooting pipe support is arranged in the mobile frame to be rocked tocause the discharge nozzle to describe a circle of given diameter withinthe furnace.

References Cited UNITED STATES PATENTS 949,290 2/ 1910 Alelder et al239-187 982,625 1/ 1911 Mitchell et al 239-187 1,541,621 6/1925 Carini239-187 2,541,695 2/ 1951 Gangewere 239-227 2,794,681 6/1057 SuessZ39-132.3 X 2,894,485 7/ 1959 Sedlacsik 118-323 X 3,130,077 4/1964Burden 239-187 X 3,170,977 2/1965 Obenchain Z39-132.3 X

FOREIGN PATENTS 1,224,130 2/1960 France.

366,442 1/ 1923 Germany.

M. HENSON WOOD, JR., Primary Examiner. V. C. WILKS, Assistant Examiner.

1. AN APPARATUS FOR APPLYING A PROTECTIVE REFRACTORY COATING TO THEREFRACTORY LINING OF A BASIC OXYGEN FURNACE WHILE ITS IS AT OR NEAROPERATING TEMPERATURE IN ORDER TO PROLONG THE LIFE OF SAID LINING,COMPRISING IN COMBINATION, A LONG RIGID SHOOTING PIPE FOR THE REFRACTORYCOATING MATERIAL EQUIPPED WITH A SUITABLE DISCHARGE NOZZLE, A LONG RIGIDSUPPORT FOR THE SHOOTING PIPE CAPABLE OF WITHSTANDING THE FURNACE HEATAND ADAPTED TO BE MOVED ENDWISE INTO AND OUT OF THE FURNACE WHEN THELATTER OCCUPIES A SUBSTANTIALLY HORIZONTAL POSITION, THE LENGTH OF SAIDSUPPORT BEING SUBSTANTIALLY EQUAL TO THE LENGTH OF THE FURNACE LINING AMOBILE FRAME CARRYING SAID SUPPORT AND LOCATED ON A PLATFORM INPROXIMITY TO THE FURNACE, SAID SUPPORT EXTENDING LONGITUDINALLY OF THEMOBILE FRAME AND WHEN LOCATED OUT OF THE FURNACE PROJECTING TOWARD THEFURNACE FOR A SUBSTANTIAL DISTANCE FROM THE FURNACE CONFRONTING END OFTHE MOBILE FRAME, AND SAID MOBILE FRAME BEING FREELY MANEUVERABLE ON THEPLATFORM TO LOCATE THE SHOOTING PIPE SUPPORT IN POSITION TO ENTER THEFURNACE AT DIFFERENT ANGLES AND THEN MOVABLE TOWARD AND FROM THE FURNACEIN EFFECTING THE MOVEMENTS OF THE SUPPORT INTO AND OUT OF THE FURNACE.